SHOCK METABOLIC RESPONSE AWADH ALQAHTANI MD MSC FRCSCSURGERYFRCSCONCOLOGY

SHOCK & METABOLIC RESPONSE AWADH ALQAHTANI MD, MSC, FRCSC(SURGERY)FRCSC(ONCOLOGY) FISC SURGICAL ONCOLOGIST AND LAPAROSCOPIC BARIATRIC SURGEON 29/09/2013

OBJECTIVES • • Definition Approach to the hypotensive patient Types Specific treatments

DEFINITION OF SHOCK • Inadequate oxygen delivery to meet metabolic demands • Results in global tissue hypoperfusion and metabolic acidosis • Shock can occur with a normal blood pressure and hypotension can occur without shock

UNDERSTANDING SHOCK • Inadequate systemic oxygen delivery activates autonomic responses to maintain systemic oxygen delivery • Sympathetic nervous system • NE, epinephrine, dopamine, and cortisol release • Causes vasoconstriction, increase in HR, and increase of cardiac contractility (cardiac output) • Renin-angiotensin axis • Water and sodium conservation and vasoconstriction • Increase in blood volume and blood pressure

UNDERSTANDING SHOCK • Cellular responses to decreased systemic oxygen delivery • ATP depletion → ion pump dysfunction • Cellular edema • Hydrolysis of cellular membranes and cellular death • Goal is to maintain cerebral and cardiac perfusion • Vasoconstriction of splanchnic, musculoskeletal, and renal blood flow • Leads to systemic metabolic lactic acidosis that overcomes the body’s compensatory mechanisms

GLOBAL TISSUE HYPOXIA • Endothelial inflammation and disruption • Inability of O 2 delivery to meet demand • Result: • Lactic acidosis • Cardiovascular insufficiency • Increased metabolic demands

MULTIORGAN DYSFUNCTION SYNDROME (MODS) • Progression of physiologic effects as shock ensues • • Cardiac depression Respiratory distress Renal failure DIC • Result is end organ failure

PATHOPHYSIOLOGY

APPROACH TO THE PATIENT IN SHOCK • ABCs • • Cardiorespiratory monitor Pulse oximetry Supplemental oxygen IV access ABG, labs Foley catheter Vital signs including rectal temperature

DIAGNOSIS • Physical exam (VS, mental status, skin color, temperature, pulses, etc) • Infectious source • Labs: • • • CBC Chemistries Lactate Coagulation studies Cultures ABG

FURTHER EVALUATION • CT of head/sinuses • Lumbar puncture • Wound cultures • Acute abdominal series • Abdominal/pelvic CT or US • Cortisol level • Fibrinogen, FDPs, D-dimer

APPROACH TO THE PATIENT IN SHOCK • History • • Recent illness Fever Chest pain, SOB Abdominal pain Comorbidities Medications Toxins/Ingestions Recent hospitalization or surgery • Baseline mental status • Physical examination • Vital Signs • CNS – mental status • Skin – color, temp, rashes, sores • CV – JVD, heart sounds • Resp – lung sounds, RR, oxygen sat, ABG • GI – abd pain, rigidity, guarding, rebound • Renal – urine output

IS THIS PATIENT IN SHOCK? • Patient looks ill • Altered mental status • Skin cool and mottled or hot and flushed • Weak or absent Yes! peripheral pulses These are all signs and • SBP <110 symptoms of shock • Tachycardia

SHOCK • Do you remember how to quickly estimate blood pressure by pulse? • If you palpate a pulse, you know SBP is at least this number 60 70 80 90

GOALS OF TREATMENT • ABCDE • • • Airway control work of Breathing optimize Circulation assure adequate oxygen Delivery achieve End points of resuscitation

AIRWAY • Determine need for intubation but remember: intubation can worsen hypotension • Sedatives can lower blood pressure • Positive pressure ventilation decreases preload • May need volume resuscitation prior to intubation to avoid hemodynamic collapse

CONTROL WORK OF BREATHING • Respiratory muscles consume a significant amount of oxygen • Tachypnea can contribute to lactic acidosis • Mechanical ventilation and sedation decrease WOB and improves survival

OPTIMIZING CIRCULATION • Isotonic crystalloids • Titrated to: • CVP 8 -12 mm Hg • Urine output 0. 5 ml/kg/hr (30 ml/hr) • Improving heart rate • May require 4 -6 L of fluids • No outcome benefit from colloids

MAINTAINING OXYGEN DELIVERY • Decrease oxygen demands • Provide analgesia and anxiolytics to relax muscles and avoid shivering • Maintain arterial oxygen saturation/content • Give supplemental oxygen • Maintain Hemoglobin > 10 g/d. L • Serial lactate levels or central venous oxygen saturations to assess tissue oxygen extraction

END POINTS OF RESUSCITATION • Goal of resuscitation is to maximize survival and minimize morbidity • Use objective hemodynamic and physiologic values to guide therapy • Goal directed approach • Urine output > 0. 5 m. L/kg/hr • CVP 8 -12 mm. Hg • MAP 65 to 90 mm. Hg • Central venous oxygen concentration > 70%

PERSISTENT HYPOTENSION • Inadequate volume resuscitation • Pneumothorax • Cardiac tamponade • Hidden bleeding • Adrenal insufficiency • Medication allergy

TYPES OF SHOCK • Hypovolemic • Septic • Cardiogenic • Anaphylactic • Neurogenic • Obstructive

CAUSES OF SHOCK

THE PROGRESSION OF SHOCK • Signs and symptoms

WHAT TYPE OF SHOCK IS THIS? Types of Shock • 68 yo M with hx of HTN and DM presents to the ER with abrupt • Hypovolemic onset of diffuse abdominal pain • Septic with radiation to his low back. The pt is hypotensive, • Cardiogenic tachycardic, afebrile, with cool • Anaphylactic but dry skin • Neurogenic Hypovolemic Shock • Obstructive

HYPOVOLEMIC SHOCK

HYPOVOLEMIC SHOCK • Non-hemorrhagic • • • Vomiting Diarrhea Bowel obstruction, pancreatitis Burns Neglect, environmental (dehydration) • • • GI bleed Trauma Massive hemoptysis AAA rupture Ectopic pregnancy, post-partum bleeding • Hemorrhagic

HYPOVOLEMIC SHOCK • ABCs • Establish 2 large bore IVs or a central line • Crystalloids • Normal Saline or Lactate Ringers • Up to 3 liters • PRBCs • O negative or cross matched • Control any bleeding • Arrange definitive treatment

EVALUATION OF HYPOVOLEMIC SHOCK • CBC • ABG/lactate • Electrolytes • BUN, Creatinine • Coagulation studies • Type and cross-match • As indicated • CXR • Pelvic x-ray • Abd/pelvis CT • Chest CT • GI endoscopy • Bronchoscopy • Vascular radiology

WHAT TYPE OF SHOCK IS THIS? • Types of Shock An 81 yo F resident of a nursing • Hypovolemic home presents to the ED with altered mental status. She is febrile to 39. 4, hypotensive with a • Septic widened pulse pressure, • Cardiogenic tachycardic, with warm extremities • Anaphylactic • Neurogenic • Obstructive Septic

SEPSIS • Two or more of SIRS criteria • • Temp > 38 or < 36 C HR > 90 RR > 20 WBC > 12, 000 or < 4, 000 • Plus the presumed existence of infection • Blood pressure can be normal!

SEPTIC SHOCK • Sepsis (remember definition? ) • Plus refractory hypotension • After bolus of 20 -40 m. L/Kg patient still has one of the following: • SBP < 90 mm Hg • MAP < 65 mm Hg • Decrease of 40 mm Hg from baseline

PATHOGENESIS OF SEPSIS Nguyen H et al. Severe Sepsis and Septic-Shock: Review of the Literature and Emergency Department Management Guidelines. Ann Emerg Med. 2006; 42: 28 -54.

SEPTIC SHOCK • Clinical signs: • • • Hyperthermia or hypothermia Tachycardia Wide pulse pressure Low blood pressure (SBP<90) Mental status changes • Beware of compensated shock! • Blood pressure may be “normal”

ANCILLARY STUDIES • Cardiac monitor • Pulse oximetry • CBC, Chem 7, coags, LFTs, lipase, UA • ABG with lactate • Blood culture x 2, urine culture • CXR • Foley catheter (why do you need this? )

TREATMENT OF SEPTIC SHOCK • 2 large bore IVs • NS IVF bolus- 1 -2 L wide open (if no contraindications) • Supplemental oxygen • Empiric antibiotics, based on suspected source, as soon as possible

TREATMENT OF SEPSIS • Antibiotics- Survival correlates with how quickly the correct drug was given • Cover gram positive and gram negative bacteria • Zosyn 3. 375 grams IV and ceftriaxone 1 gram IV or • Imipenem 1 gram IV • Add additional coverage as indicated • Pseudomonas- Gentamicin or Cefepime • MRSA- Vancomycin • Intra-abdominal or head/neck anaerobic infections. Clindamycin or Metronidazole • Asplenic- Ceftriaxone for N. meningitidis, H. infuenzae • Neutropenic – Cefepime or Imipenem

PERSISTENT HYPOTENSION • If no response after 2 -3 L IVF, start a vasopressor (norepinephrine, dopamine, etc) and titrate to effect • Goal: MAP > 60 • Consider adrenal insufficiency: hydrocortisone 100 mg IV

WHAT TYPE OF SHOCK IS THIS? • Types of Shock A 55 yo M with hx of HTN, DM presents with “crushing” • Hypovolemic substernal CP, diaphoresis, hypotension, tachycardia and • Septic cool, clammy extremities • Cardiogenic • Anaphylactic • Neurogenic • Obstructive Cardiogenic

CARDIOGENIC SHOCK

CARDIOGENIC SHOCK • Defined as: • SBP < 90 mm. Hg • CI < 2. 2 L/m/m 2 • PCWP > 18 mm. Hg • Signs: • Cool, mottled skin • Tachypnea • Hypotension • Altered mental status • Narrowed pulse pressure • Rales, murmur

ETIOLOGIES • What are some causes of cardiogenic shock? • • • AMI Sepsis Myocarditis Myocardial contusion Aortic or mitral stenosis, HCM Acute aortic insufficiency

PATHOPHYSIOLOGY OF CARDIOGENIC SHOCK • Often after ischemia, loss of LV function • Lose 40% of LV clinical shock ensues • CO reduction = lactic acidosis, hypoxia • Stroke volume is reduced • Tachycardia develops as compensation • Ischemia and infarction worsens

ANCILLARY TESTS • EKG • CXR • CBC, Chem 10, cardiac enzymes, coagulation studies • Echocardiogram

TREATMENT OF CARDIOGENIC SHOCK • Goals- Airway stability and improving myocardial pump function • Cardiac monitor, pulse oximetry • Supplemental oxygen, IV access • Intubation will decrease preload and result in hypotension • Be prepared to give fluid bolus

TREATMENT OF CARDIOGENIC SHOCK • AMI • Aspirin, beta blocker, morphine, heparin • If no pulmonary edema, IV fluid challenge • If pulmonary edema • Dopamine – will ↑ HR and thus cardiac work • Dobutamine – May drop blood pressure • Combination therapy may be more effective • PCI or thrombolytics • RV infarct • Fluids and Dobutamine (no NTG) • Acute mitral regurgitation or VSD • Pressors (Dobutamine and Nitroprusside)

WHAT TYPE OF SHOCK IS THIS? • Types of Shock A 34 yo F presents to the ER after dining at a restaurant where shortly • Hypovolemic after eating the first few bites of her • Septic meal, became anxious, diaphoretic, began wheezing, noted diffuse • Cardiogenic pruritic rash, nausea, and a sensation • Anaphylactic of her “throat closing off”. She is currently hypotensive, tachycardic • Neurogenic and ill appearing. • Obstructive Anaphalactic

ANAPHYLACTIC SHOCK • Anaphylaxis – a severe systemic hypersensitivity reaction characterized by multisystem involvement • Ig. E mediated

ANAPHYLACTIC SHOCK • What are some symptoms of anaphylaxis? • First- Pruritus, flushing, urticaria appear • Next- Throat fullness, anxiety, chest tightness, shortness of breath and lightheadedness • Finally- Altered mental status, respiratory distress and circulatory collapse

ANAPHYLACTIC SHOCK- DIAGNOSIS • Clinical diagnosis • Defined by airway compromise, hypotension, or involvement of cutaneous, respiratory, or GI systems • Look for exposure to drug, food, or insect • Labs have no role

ANAPHYLACTIC SHOCK- TREATMENT • ABC’s • Angioedema and respiratory compromise require immediate intubation • IV, cardiac monitor, pulse oximetry • IVFs, oxygen • Epinephrine • Second line • Corticosteriods • H 1 and H 2 blockers

ANAPHYLACTIC SHOCK- TREATMENT • Epinephrine • 0. 3 mg IM of 1: 1000 (epi-pen) • Repeat every 5 -10 min as needed • Caution with patients taking beta blockers- can cause severe hypertension due to unopposed alpha stimulation • For CV collapse, 1 mg IV of 1: 10, 000 • If refractory, start IV drip

ANAPHYLACTIC SHOCK - TREATMENT • Corticosteroids • Methylprednisolone 125 mg IV • Prednisone 60 mg PO • Antihistamines • H 1 blocker- Diphenhydramine 25 -50 mg IV • H 2 blocker- Ranitidine 50 mg IV • Bronchodilators • Albuterol nebulizer • Atrovent nebulizer • Magnesium sulfate 2 g IV over 20 minutes • Glucagon • For patients taking beta blockers and with refractory hypotension • 1 mg IV q 5 minutes until hypotension resolves

WHAT TYPE OF SHOCK IS THIS? • A 41 yo M presents to the ER after an MVC complaining of decreased sensation below his waist and is now hypotensive, bradycardic, with warm extremities Neurogenic Types of Shock • Hypovolemic • Septic • Cardiogenic • Anaphylactic • Neurogenic • Obstructive

NEUROGENIC SHOCK

NEUROGENIC SHOCK • Occurs after acute spinal cord injury • Sympathetic outflow is disrupted leaving unopposed vagal tone • Results in hypotension and bradycardia

NEUROGENIC SHOCK • Loss of sympathetic tone results in warm and dry skin • Shock usually lasts from 1 to 3 weeks • Any injury above T 1 can disrupt the entire sympathetic system • Higher injuries = worse paralysis

NEUROGENIC SHOCK- TREATMENT • A, B, Cs • Remember c-spine precautions • Fluid resuscitation • Keep MAP at 85 -90 mm Hg for first 7 days • Thought to minimize secondary cord injury • If crystalloid is insufficient use vasopressors • Search for other causes of hypotension • For bradycardia • Atropine • Pacemaker

NEUROGENIC SHOCK- TREATMENT • Methylprednisolone • • Used only for blunt spinal cord injury High dose therapy for 23 hours Must be started within 8 hours Controversial- Risk for infection, GI bleed

WHAT TYPE OF SHOCK IS THIS? • Types of Shock A 24 yo M presents to the ED after an MVC c/o chest pain and • Hypovolemic difficulty breathing. On PE, you • Septic note the pt to be tachycardic, hypotensive, hypoxic, and with • Cardiogenic decreased breath sounds on left • Anaphylactic • Neurogenic • Obstructive

OBSTRUCTIVE SHOCK

OBSTRUCTIVE SHOCK • Tension pneumothorax • Air trapped in pleural space with 1 way valve, air/pressure builds up • Mediastinum shifted impeding venous return • Chest pain, SOB, decreased breath sounds • No tests needed! • Rx: Needle decompression, chest tube

OBSTRUCTIVE SHOCK • Cardiac tamponade • Blood in pericardial sac prevents venous return to and contraction of heart • Related to trauma, pericarditis, MI • Beck’s triad: hypotension, muffled heart sounds, JVD • Diagnosis: large heart CXR, echo • Rx: Pericardiocentisis

OBSTRUCTIVE SHOCK • Pulmonary embolism • • • Virscow triad: hypercoaguable, venous injury, venostasis Signs: Tachypnea, tachycardia, hypoxia Low risk: D-dimer Higher risk: CT chest or VQ scan Rx: Heparin, consider thrombolytics

OBSTRUCTIVE SHOCK • Aortic stenosis • • • Resistance to systolic ejection causes decreased cardiac function Chest pain with syncope Systolic ejection murmur Diagnosed with echo Vasodilators (NTG) will drop pressure! Rx: Valve surgery

REVIEW 1. The term “shock” is MOST accurately defined as: A. a decreased supply of oxygen to the brain. B. cardiovascular collapse leading to inadequate perfusion. C. decreased circulation of blood within the venous circulation. D. decreased function of the respiratory system leading to hypoxia.

REVIEW 3. Signs of compensated shock include all of the following, EXCEPT: A. restlessness or anxiety. B. pale, cool, clammy skin. C. a feeling of impending doom. D. weak or absent peripheral pulses.

REVIEW 6. A 60 -year-old woman presents with a BP of 80/60 mm Hg, a pulse rate of 110 beats/min, mottled skin, and a temperature of 103. 9°F. She is MOST likely experiencing: A. septic shock. B. neurogenic shock. C. profound heart failure. D. a severe viral infection.

THE END ANY QUESTIONS?